Device for the installation of vacuum consolidation dewatering horizontal drains for dewatering sludge ponds

ABSTRACT

A device for installing horizontal drains in a coal combustion residual or other sludge pond consists of a trenching device that extends downwardly to the depth of required installation of the drains and an attachment through which the drains are fed during installation. The trenching device and attachment are mounted onto a carrier for floatation of the required equipment on the surface of a water-filled sludge pond. The carrier can be winched, hauled or driven across the surface of the sludge. A hydraulic system may be used to raise and lower the trenching device and attachment. The trenching device may be equipped with a chain driven blade mechanism or dredging device for the purpose of cutting a trench into the pond sludge, and a vibratory trenching device may be used to effectively liquefy the material to make the trenching device easier to pull or tow through the sludge in the pond.

PRIORITY STATEMENT Under 35 U.S.C. § 119 & 37 C.F.R. § 1.78

This non-provisional application claims priority based upon prior U.S.Provisional Patent Application Ser. No. 62/411,992 filed Oct. 24, 2016,in the names of David Seeger, Steven Kosler, David Morett, and MichaelFontenot entitled “DEVICE FOR THE INSTALLATION OF VACUUM CONSOLIDATIONDEWATERING HORIZONTAL DRAINS FOR DEWATERING SLUDGE PONDS,” thedisclosures of which are incorporated herein in their entirety byreference as if fully set forth herein.

FIELD OF INVENTION

This invention relates to a device for the installation of horizontaldrains below the surface of a sludge pond for the purpose of removingthe water from (dewatering) the sludge. Various methods of usinghorizontal drains for dewatering sludge are generally known in the artand are referred to here as vacuum consolidation dewatering (VCD). Thisinvention will describe a device used to install the drains below thesurface of the sludge pond for the purpose of applying VCD.

BACKGROUND OF THE INVENTION

A variety of industries produce waste from operating processes that areaccumulated in sludge ponds or tailing ponds, for example, coalcombustion residuals (CCR) sediments in disposal ponds or impoundments.These ponds may require dewatering to mitigate their impact on theneighboring environment and human or animal health. Frequently local,state and federal governments may regulate aspects of managing theseponds and, in the case of CCR ponds, closure is also now required byU.S. environmental regulation.

CCR is known to be unstable when saturated. When saturated CCR issubject to shear strain, it densifies and expels water, resulting in anear total loss of shear strength. In this state, the material becomes aviscous fluid and may begin to slide or flow. This process may result inovertopping of impoundments and makes excavation and handling difficultto impossible. Reducing the water content of the CCR material by only afew percentage points has a dramatic effect on its behavior, allowingstable, near vertical cuts suitable for mass excavation.

Therefore, to facilitate closure, the ponds are sometimes dewatered bypre-drainage of the sludge to enhance strength and stability of thematerial and thereby provide a stable surface on which to operateearthmoving and grading equipment. VCD is one option for dewatering thesludge.

A typical VCD system consists of prefabricated drains made from plasticcores with a geotextile envelope or perforated plastic pipe or tubesurrounded by a geotextile envelope, installed horizontally at anear-coplanar depth below the surface of the sludge pond. The drains areinstalled in a pattern throughout the area of the sludge pond that is tobe dewatered. Herein is described a novel device useful in installingthe horizontal drains.

SUMMARY OF THE INVENTION

A device that can be used to install horizontal drains in a sludge pondconsists of a plow or other trenching device that extends to the depthof required installation into the pond and an attachment through whichthe drains are fed during installation. The trenching device andattachment are mounted onto a carrier that is capable of floating all ofthe associated equipment on the surface of a saturated and/orwater-filled sludge pond, and can be winched or hauled across thesurface of the sludge by winching devices. Various embodiments of thedevice may have a hydraulic system to raise and lower the trenchingdevice apparatus and also, or alternatively, may include equipment forgenerating the power required to operate the hydraulic system.

Some embodiments of the device of the present invention include alocation to carry the drain to be installed and storage for the requiredtools and hoses or pipes for connecting the drains to the vacuum andwater pump unit that is part of the VCD system located near the draininstallation area. In some embodiments, the device will also include aprotected operator cab where the operator can either control thewinches, or communicate with support staff. In such embodiments, theprotected cab should provide adequate protection for the operator in theevent that the winch cable should break.

In some embodiments the device could be towed behind suitable mechanizedpond-compatible equipment in place of being moved by winches. A suitablehitching mechanism would be added to the device so that it could beconnected to or trailed behind a pond-compatible mechanized vessel.

In some embodiments, the trenching device could have a chain drivenblade mechanism or trenching device for the purpose of cutting a trenchinto the pond sludge. This embodiment could provide a reduced energyrequirement of the equipment towing or of the winches pulling the VCDinstallation device across the surface of the sludge pond. The use of ablade mechanism or trencher may enable moving the device duringinstallation (i.e., if the sludge is too hard or too solid, the towingequipment or the winches may be unable to move the trenching deviceacross the pond, the chain trencher will solve that problem). Avibratory plow or trenching device may be used to effectively liquefythe material to make the trenching device easier to pull or tow throughthe sludge in the pond. This modification includes a vibrating devicemounted to the shaft of the trenching device to vibrate the shaft duringinstallation which will liquefy the sludge material of the pond makingit easier to pull or tow the trenching device through the sludge.

Additionally in some embodiments, the carrier may have tracks to aid inmoving the VCD installation device across dry sections of sludge ratherthan dragging the carrier across the sludge surface. These tracks may ormay not be mechanized or self-propelled.

In yet another embodiment, the VCD installation device may include thesimultaneous installation of drains at multiple depths in the sludgebelow the pond surface. Some ponds may be more effectively drained bythe installation of drains at multiple depths below the surface. Thetrenching device may be modified to include the option of installingdrains at different depths, for example, one drain may be installed at adepth of ten feet below the surface and a second drain at five feetbelow the surface.

Alternately, the trenching device may be modified to install drains atmore than two depths below the surface simultaneously (i.e., drainscould conceivably be installed every foot below the surface extendingthe full length of the trenching device shaft). For example, a fifteenfeet long trenching device shaft could be modified to include draininstallation at depths of fifteen feet below the surface and one ft.above that extending to the surface, i.e., installation of drains atfifteen feet below the surface, fourteen feet, thirteen feet, twelvefeet, etc., extending to one foot below the surface.

The foregoing has outlined rather broadly certain aspects of the presentinvention in order that the detailed description of the invention thatfollows may better be understood. Additional features and advantages ofthe invention will be described hereinafter which form the subject ofthe claims of the invention. It should be appreciated by those skilledin the art that the conception and specific embodiment disclosed may bereadily utilized as a basis for modifying or designing other structuresor processes for carrying out the same purposes of the presentinvention. It should also be realized by those skilled in the art thatsuch equivalent constructions do not depart from the spirit and scope ofthe invention as set forth in the appended claims.

DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1A is a diagram showing the side view of one embodiment of a VCDinstallation device having both a towing hitch and winch connections formoving the device;

FIG. 1B is a diagram showing the top view thereof;

FIG. 2A is a diagram showing the side view of the VCD installationdevice having the hitch and winch options shown in FIG. 1 in addition toa track over the carrier for the purpose of assisting with moving theinstallation device across solid sludge surface. These tracks may or maynot be mechanized or self-propelled;

FIG. 2B is a diagram showing the top view thereof;

FIG. 3A is a diagram of the VCD installation device having the hitch andwinch options shown in FIG. 1 in addition to a cutting blade precedingthe trenching device in order to help dig a trench through anydifficult-to-traverse materials;

FIG. 3B is a diagram showing the top view thereof;

FIG. 4A is a diagram of the VCD installation device having the hitch andwinch options shown in FIG. 1 and both the track and cutting bladeoptions depicted in FIG. 3 and FIG. 4;

FIG. 4B is a diagram showing the top view thereof;

FIG. 5A is a diagram of the VCD installation device having the hitch andwinch options shown in FIG. 1 and having the option of installing drainsat multiple depths below the surface of the pond;

FIG. 5B is a diagram showing the top view thereof;

FIG. 6A is a diagram of the VCD installation device having the hitch andwinch options shown in FIG. 1 and having the option of a vibratorytrenching device where a vibrating device is mounted on the trenchingdevice shaft to impart vibrating energy to the trenching device duringinstallation;

FIG. 6B is a diagram showing the top view thereof; and

FIG. 7 is a diagram of the VCD installation device having the hitch andwinch options shown in FIG. 1 and having the option of a trencher inplace of the trenching device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to improved methods and systems for,among other things, the installation of vacuum consolidation dewateringhorizontal drains for dewatering sludge ponds. The configuration and useof the presently preferred embodiments are discussed in detail below. Itshould be appreciated, however, that the present invention provides manyapplicable inventive concepts that can be embodied in a wide variety ofcontexts other than device for the installation of vacuum consolidationdewatering sludge ponds. Accordingly, the specific embodiments discussedare merely illustrative of specific ways to make and use the invention,and do not limit the scope of the invention.

Embodiments of the present invention include a device for theinstallation of the prefabricated drains in a horizontal, co-planarpattern below the surface of a sludge pond with the intent of putting avacuum on the horizontal drains to withdraw water from the sludge pondmaterial to dewater the sludge to the level of the drains below the pondsurface.

Referring now to FIG. 1A and FIG. 1B which shows one embodiment of theVCD installation device 100 comprising a trenching device 101 thatextends below the surface of the pond to a depth 120 of 1-15 feet and adrain/hose downtube 102 through which the drain 106 or hose 108 passesto be installed at depth 120 beneath the pond surface. The trenchingdevice 101 and downtube 102 can be raised and lowered below the surfaceusing the hydraulic system 104 which is powered by the motor 110. Thedrain 106 and hose 108 are in coils on reels that are mounted on afeeder and unroll during installation as the VCD installation device 100moves across the pond so that the drain 106 or hose 108 may be fed downthe downtube 102 for installation at a certain depth 120. The trenchingdevice 101, downtube 102, feeders, hydraulic system 104, and motor aremounted on a carrier 112 so that the entire VCD installation device 100can float on the water surface of a sludge pond.

The VCD installation device 100 may be winched across the surface of thepond using the winch connections 114 on the device. Alternately, the VCDinstallation device 100 may be towed across the surface of the pondbehind a suitable piece of heavy equipment using a hitch 116 on thedevice. In addition, either the hitch 116 or winch connection 114 can beused to haul the VCD installation device 100 to the next point at whicha drain 106 should be installed into the pond.

Referring now to FIG. 2A and FIG. 2B which shows an alternativeembodiment of the device described above and shown in FIG. 1A and FIG.1B with the addition of a rolling belt or track 130 that is mounted onthe surface of the carrier in a continuous loop front to back so that ifthe device is winched or hauled across a dry sludge pile extending abovethe water surface of the pond, the tracks 130 will grip the sludge androll, allowing easier travel of the VCD installation device 100 whereaswith no rolling track the bottom surface of the carrier 112 would bedragged across the abrasive solid sludge. Alternately, some sludge pondsare relatively dry where a limited amount, or no, free water is present.In these ponds, the VCD installation device 100 would be dragged acrossthe surface of that pond. However, if the rolling tracks 130 areincluded on the carrier 112, then the VCD installation device 100 willroll easier, with less resistance, across the relatively dry pondsurface. The rolling tracks 130 prevent the wearing or abrading of thebottom surface of the carrier 112 because the bare bottom of the deviceis not being dragged across the dry pond surface which may be abrasive.The rolling tracks may also be mechanized to self-propel the deviceacross the pond surface.

Referring now to FIG. 3A and FIG. 3B which shows another alternativeembodiment of the device described above and shown in FIG. 1A and FIG.1B with the addition of a cutting blade or chain trencher 124 which canbe used to dig or trench the sludge in the pond to the required depth120. Some sludge material could be too strong or hard to plow throughand will need to be dug out to make a path for the installation of thedrain 106 or hose 108. In addition to the chain trencher 124 there isalso a required motor 126 and chain drive 128 required to drive thechain trencher 124 to dig the hole for drain 106 or hose 108installation. In some embodiments, the chain trencher 124 may beconfigured with a circular saw blade instead of a cutting chain wherethe radius of the required depth of the VCD drain installation is theradius of the circular saw blade.

Those skilled in the art will recognize that the devices described aboveand shown on FIG. 1A and FIG. 1B, FIGS. 2A and 2B, and FIGS. 3A and 3Bcould be included in one device such as shown in FIG. 4A and FIG. 4B.

Referring now to FIG. 5A and FIG. 5B which shows another embodiment ofthe device described above and shown in FIG. 1A and FIG. 1B with theaddition of an option to simultaneously install the drains 106 or hoses108 at multiple depths below the surface of the pond. Multiple downtubes102, 134 are used to install drains 106 or hoses 108 at varying depths120, 136 below the surface. Although the installation of drains 106 orhoses 108 is shown at two depths, those skilled in the art willappreciate that there could be drain 106 or hose 108 installations at anumber of depths, such as at depths varying by one foot extending alongthe entire length of the trenching device shaft. For example, a fifteenfoot long trenching device shaft could be modified to include draininstallation at depths of fifteen feet below the surface and one ft.above that extending to the surface, i.e., installation of drains 106 orhoses 108 at fifteen feet below the surface, fourteen feet, thirteenfeet, twelve feet, etc., extending at one foot intervals to 1 foot belowthe surface. This embodiment could also include the track 130, cuttingblade 124 or vibratory trenching device 132 modifications shown in FIG.2A and FIG. 2B, FIG. 3A and FIG. 3B and FIG. 6A and FIG. 6B,respectively.

Referring now to FIG. 6A and FIG. 6B which shows another embodiment ofthe device described above and shown in FIG. 1A and FIG. 1B with anoption to modify the trenching device 101 by attachment of a vibratingdevice 132 to depart vibrational energy to the trenching device 101during installation. During installation, the vibrating energy of thevibrating trenching device 101 will cause the sludge to liquefy to acertain extent which allows the VCD installation device 100 to be moreeasily pulled or towed through the sludge. This embodiment could alsoinclude the track 130 option shown in FIG. 2, and/or the option ofinstalling of drains 106 or hoses 108 at multiple depths 120, 136 belowthe surface of the pond as shown in FIG. 5A and FIG. 5B.

Referring now to FIG. 7 which shows another embodiment of the devicedescribed above except that the trenching device 101 has been replacedby a trencher 138 which can be used to dig the sludge pond and make apath for the drains 106 or hoses 108 to be installed. Using a trencher138 to make a path or trench in the sludge pond to install the drains106 or hoses 108 reduces the drag on the VCD installation device 100.Some sludge material could be too strong or hard to plow through and atrencher 138 could be used to dig a path for the installation of thedrains 106 or hoses 108. The trencher 138 may also require less energyto move the carrier 112 across the pond by reducing the drag on theoverall VCD installation device 100.

While the present device has been disclosed according to the preferredembodiment of the invention, those of ordinary skill in the art willunderstand that other embodiments have also been enabled. Even thoughthe foregoing discussion has focused on particular embodiments, it isunderstood that other configurations are contemplated. In particular,even though the expressions “in one embodiment” or “in anotherembodiment” are used herein, these phrases are meant to generallyreference embodiment possibilities and are not intended to limit theinvention to those particular embodiment configurations. These terms mayreference the same or different embodiments, and unless indicatedotherwise, are combinable into aggregate embodiments. The terms “a”,“an” and “the” mean “one or more” unless expressly specified otherwise.

When a single embodiment is described herein, it will be readilyapparent that more than one embodiment may be used in place of a singleembodiment. Similarly, where more than one embodiment is describedherein, it will be readily apparent that a single embodiment may besubstituted for that one device.

In light of the wide variety of plowing methods and systems available,the detailed embodiments are intended to be illustrative only and shouldnot be taken as limiting the scope of the invention. Rather, what areclaimed as the invention are all such modifications as may come withinthe spirit and scope of the following claims and equivalents thereto.

None of the description in this specification should be read as implyingthat any particular element, step or function is an essential elementwhich must be included in the claim scope. The scope of the patentedsubject matter is defined only by the allowed claims and theirequivalents. Unless explicitly recited, other aspects of the presentinvention as described in this specification do not limit the scope ofthe claims.”

While the present system and method has been disclosed according to thepreferred embodiment of the invention, those of ordinary skill in theart will understand that other embodiments have also been enabled. Eventhough the foregoing discussion has focused on particular embodiments,it is understood that other configurations are contemplated. Inparticular, even though the expressions “in one embodiment” or “inanother embodiment” are used herein, these phrases are meant togenerally reference embodiment possibilities and are not intended tolimit the invention to those particular embodiment configurations. Theseterms may reference the same or different embodiments, and unlessindicated otherwise, are combinable into aggregate embodiments. Theterms “a”, “an” and “the” mean “one or more” unless expressly specifiedotherwise. The term “connected” means “communicatively connected” unlessotherwise defined.

When a single embodiment is described herein, it will be readilyapparent that more than one embodiment may be used in place of a singleembodiment. Similarly, where more than one embodiment is describedherein, it will be readily apparent that a single embodiment may besubstituted for that one device.

In light of the wide variety of methods for device for the installationof vacuum consolidation dewatering horizontal drains for dewateringsludge ponds known in the art, the detailed embodiments are intended tobe illustrative only and should not be taken as limiting the scope ofthe invention. Rather, what is claimed as the invention is all suchmodifications as may come within the spirit and scope of the followingclaims and equivalents thereto.

None of the description in this specification should be read as implyingthat any particular element, step or function is an essential elementwhich must be included in the claim scope. The scope of the patentedsubject matter is defined only by the allowed claims and theirequivalents. Unless explicitly recited, other aspects of the presentinvention as described in this specification do not limit the scope ofthe claims.

We claim:
 1. A method for installing a drain into a sludge pond,comprising: cutting a trench in a sludge pond at a single depth with atrenching device attached to a amphibious carrier; passing a drain intothe trench through a downtube coupled with the trenching device; andtransporting the amphibious carrier across the sludge pond.
 2. Themethod of claim 1, further including removing water from the sludge pondthrough the drain with a vacuum.
 3. The method of claim 1, furtherincluding removing water from the sludge pond through the drain with awater pump.
 4. The method of claim 1, further including multipledowntubes for simultaneous installation of co-planar drains at multipledepths.
 5. The method of claim 1, further including transporting thecarrier across the sludge pond with a winch.
 6. The method of claim 1,further including cutting a trench in the sludge pond with a chaindriven blade attached to the trenching device.
 7. The method of claim 1,further including liquefying sludge in the sludge pond with a vibratorattached to the trenching device.
 8. The method of claim 1, furtherincluding transporting the carrier across dry sections of sludge withtracks attached to the carrier.
 9. A device, comprising: a trenchingdevice that cuts a trench in a sludge pond extending downwardly from acarrier to a single depth; a downtube through which drain may be passedinto the trench coupled with the trenching device; and a amphibiouscarrier for transporting the trenching device across the sludge pond.10. The trenching device of claim 9, further including vacuum attachedto the drain to remove water from the sludge pond.
 11. The trenchingdevice of claim 9, further including a water pump attached to the drainto remove water from the sludge pond.
 12. The trenching device of claim9, further including multiple downtubes for simultaneous installation ofco-planar drains at multiple depths.
 13. The trenching device of claim9, wherein the winch is attached to a motorized vessel.
 14. Thetrenching device of claim 9, wherein the trenching device is equippedwith a chain driven blade to assist in cutting a trench in the sludgepond.
 15. The trenching device of claim 9, wherein the trenching deviceis equipped with a vibrator to liquefy sludge in the sludge pond as thetrenching device cuts the trench in the sludge pond.
 16. The trenchingdevice of claim 9, wherein the carrier is equipped with tracks to aid inmoving the carrier across dry sections of sludge.